The two columns with
barril in their head and the column headed terço should be viewed
skeptically. We are not even certain that the
terço
existed during this period. The dictionaries by Transtagno (1773) and Elwes (5th ed.
1907, page 264) say a quartola is half a pipa.
The literature mentions units not shown here, but with little corroboration,
such as a quartaõ = 3 canadas and a quadeiro = 5 alqueires. Moreover, strange equivalences occur, such as 1 canada = 5 alqueires, and 1 almude = 11 canadas. So we expect this chart to evolve.

The numbers that have been taken directly from the literature, not calculated,
have superscripts that identify their source. Those meanings are given below.
Question marks identify suspect equivalencies we calculated. In the rows of equivalents in
liters, the root value given by or calculated from the source is shown in
boldface. The other values in the row were calculated from that root.

The smallest units were consumer or tavern measures; the tonel
was so large it was rarely used. In many locations either the size of units or their
relationship to other units, or both, differed from the Lisbon standard. For
example, 1 almude contained 12 canada almost everywhere, yet there were towns
where it contained 10, 11 even 14 canadas. The liquid measures of the city of
Porto were all larger than those of Lisbon.